AUTHOR=Joshi Deepak , Pan Xiaoling , McFadden Michael J. , Bevins David , Liang Xiao , Lu Peng , Thiem Suzanne , Xi Zhiyong 

TITLE=The Maternally Inheritable Wolbachia wAlbB Induces Refractoriness to Plasmodium berghei in Anopheles stephensi

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.00366

DOI=10.3389/fmicb.2017.00366

ISSN=1664-302X

ABSTRACT=<p>The endosymbiont <italic>Wolbachia w</italic>AlbB induces refractoriness to <italic>Plasmodium falciparum</italic> in <italic>Anopheles stephensi</italic>, the primary mosquito vector of human malaria in the Middle East and South Asia. However, it remains unknown whether such refractoriness can be extended to other malaria species. In particular, it was reported that under very specific conditions, <italic>w</italic>AlbB can enhance <italic>Plasmodium</italic> infection in some hosts. Here, we measured the impact of <italic>w</italic>AlbB on the rodent malaria parasite <italic>Plasmodium berghei</italic> in <italic>A. stephensi</italic> by comparing the load of oocysts and sporozoites in midguts and salivary glands, respectively, between <italic>w</italic>AlbB-infected and -uninfected mosquitoes. To investigate whether <italic>w</italic>AlbB modulated mosquito immune defense against parasites, we compared the expression of the immune genes, which were previously reported to involve in antimalarial response, in both midguts and the remaining carcass tissues of mosquitoes. The stable association of <italic>w</italic>AlbB with <italic>A. stephensi</italic> resulted in reduction of parasites by more than half at the oocyst stage, and up to 91.8% at the sporzoite stage. The anti-<italic>plasmodium</italic> immune genes, including <italic>TEP1</italic>, <italic>LRIM1</italic>, Toll pathway gene <italic>Rel1</italic> and the effector <italic>Defensin 1</italic>, were induced by <italic>w</italic>AlbB in different mosquito body tissues. These findings suggest that immune priming is a potential cause of <italic>w</italic>AlbB-mediated antimalarial response in <italic>A. stephensi</italic>. More importantly, no evidence was found for any enhancement of <italic>Plasmodium</italic> infection in <italic>A. stephensi</italic> stably infected with <italic>w</italic>AlbB. We discuss these findings with possible implementations of <italic>Wolbachia</italic> for malaria control in disease endemic areas.</p>